Radio frequency device for resurfacing skin and method

ABSTRACT

A radio frequency device for use on a human to resurface skin having collagen therein. The device includes a handle member having an end portion adapted for engaging the skin. At least one passageway extends through the handle member to an opening at the end portion. An electrically conductive liquid is supplied through the passageway to the opening. An electrode is carried by the end portion in communication with the passageway. Radio frequency energy supplied to the electrode causes the collagen in the skin to contract and thus tighten the skin.

CROSS-REFERENCE TO RELATED APPLICATION

This is a division of application Ser. No. 08/886,580 filed Jul. 1,1997, now U.S. Pat. No. 5,843,078.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to devices and methods for resurfacing skin and,more particularly, to devices and methods for treating wrinkles.

2. Description of the Related Art

Devices utilizing laser energy exist for resurfacing or tightening skin.These devices burn the skin with a superficial application of laserenergy which is sufficient to penetrate the subdermal layers and causeshrinkage of the collagen components of these deep skin layers.Unfortunately, these devices produce a second degree burn in the outerlayers of the skin which is painful and results in sloughing of theselayers. There is, therefore, a need for a new and improved device whichovercomes these advantages.

OBJECTS OF THE INVENTION

In general, it is an object of the present invention to provide a radiofrequency device and method for resurfacing skin.

Another object of the invention is to provide a radio frequency deviceand method of the above character in which collagen molecules in theskin are denatured to tighten the epidermis layer of the skin.

Another object of the invention is to provide a radio frequency deviceand method of the above character in which the subdermal layers of theskin are heated to denature the collagen therein.

Another object of the invention is to provide a radio frequency deviceand method of the above character which minimizes burning of thesuperficial layers of the skin.

Another object of the invention is to provide a radio frequency deviceand method of the above character in which radio frequency energy iscarried by an electrically conductive liquid to the surface of the skin.

Another object of the invention is to provide a radio frequency deviceand method of the above character in which a flow of the electricallyconductive liquid engages the skin to actively cool the skin.

Additional objects and features of the invention will appear from thefollowing description in which the preferred embodiments are set forthin detail in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view of the radio frequency device for thepresent invention.

FIG. 2 is an enlarged fragmentary view of a portion of the radiofrequency device of FIG. 1 taken along the line 2—2 of FIG. 1.

FIG. 3 is a cross-sectional view of the radio frequency device of FIG. 1taken along the line 3—3 of FIG. 2.

FIG. 4 is a cross-sectional view of the radio frequency device of FIG. 1taken along the line 4—4 of FIG. 3.

FIG. 5 is a cross-sectional view of the radio frequency device of FIG. 1taken along the line 5—5 of FIG. 4.

FIG. 6 is an enlarged fragmentary top plan view of the radio frequencydevice of FIG. 1 taken along the line 6—6 of FIG. 1.

FIG. 7 is a cross-sectional view of the radio frequency device of FIG. 1taken along the line 7—7 of FIG. 6.

FIG. 8 is a graph of the optimal temperature gradient across thethickness of the skin achieved with the radio frequency device andmethod of the present invention.

SUMMARY OF THE INVENTION

In general, a radio frequency device is provided for use on a human toresurface skin having collagen therein. The device includes a handlemember having an end portion adapted for engaging the skin. At least onepassageway extends through the handle member to an opening at the endportion. Means coupled to the handle member supplies an electricallyconductive liquid through the passageway to the opening. An electrode iscarried by the end portion in communication with the passageway. Meansfor supplying radio frequency energy to the electrode is included. Theradio frequency energy causes the collagen in the skin to contract andthus tighten the skin.

DETAILED DESCRIPTION OF THE INVENTION

More in particular, a medical apparatus or device 16 is provided forsupplying radio frequency energy to the skin 17 of a patient forresurfacing the skin 17 (see FIG. 1). Radio frequency device 16 isparticularly suited for treating wrinkles 18 formed in skin 17. Thedevice 16 is made from a body or handle member 22 having handle means inthe form of handle 23 adapted for grasping by the operator and an endportion in the form of elongate cylindrical tube 24 adapted for engagingthe skin of the patient. Tubular member or tube 24, as shown morespecifically in FIGS. 2-5, has proximal and distal extremities 24 a and24 b and extends along a central longitudinal axis 26. At least onelumen or passageway 27 extends from proximal extremity 24 a to anopening or orifice 28 at distal extremity 24 b. First passageway 27 isformed by a cylindrical inner surface 29 of tube 24. Tube 24 has aninner diameter ranging from 0.2 inch to 1.5 inches. The tube 24 has aproximal portion 31 made from any suitable clear material such aspolyethylene or polyester and a distal end 32 made from any suitablepliable, nonconductive material such as Buna rubber so as to permitdistal end 32 to conform to the shape of the skin 17 on which it isplaced. Distal end 32 is secured to proximal portion 31 by any suitablemeans such as an adhesive (not shown). The distal end 32 has alongitudinal dimension or length of approximately 0.5 inch and is formedwith a generally planar end surface 33 disposed at an angle ofapproximately 45° to 80° relative to longitudinal axis 26.

Handle 23 has a shape adapted for grasping by a human hand, as shown inFIG. 1, and is made from any suitable rigid material such asacrylonitrile butadiene styrene (ABS), nylon, polyethylene or polyester.Tube proximal extremity 24 a is connected to handle 23 by any suitablemeans such as an adhesive (not shown). Alternatively, tube 24 can beformed integral with handle 23 and be within the scope of the presentinvention.

First passageway 27 has a cross-sectional area to permit a flow of aliquid to travel therethrough to skin 17 at orifice 28. The liquidtraveling through the first passageway is an electrically conductiveliquid and can be in the form of a liquid having relatively highviscosity, such as two centipoise. Alternatively, the electricallyconductive liquid or electrolytic solution can be a saline solution andbe within the scope of the present invention. A tubular member or tube36 extends from a conventional supply pouch or container 37 having theelectrolytic solution therein through handle 23 for supplying theelectrolytic solution to tube 24. Supply tube 36 can be of any suitabletype such as flexible surgical tubing and is provided with an internalpassageway (not shown) which communicates with first or supplypassageway 27 of tube 24. Means in the form of a conventional variableflow IV clamp 38 is carried by tube 36 external of radio frequencydevice 16 for regulating the flow of electrolytic solution through tube36.

Tube 24 is provided with an additional passageway extending between itsproximal and distal extremities 24 a and 24 b for removing theelectrolytic solution from skin 17. A second tubular member or innertube 41 is disposed within tube 24 in this regard. Inner tube 41 is madefrom any suitable material such as ABS, nylon, polyethylene orpolyester. As illustrated in FIGS. 2-4, inner tube 41 has proximal anddistal extremities 41 a and 41 b and is provided with a passageway inthe form of second passageway 42 extending longitudinally therethrough.The material of inner tube 41 can be clear to permit viewing of thefluid traveling therethrough. Inner tube 41 extends along the top oftube 24 and is secured to cylindrical inner surface 29 by any suitablemeans such as epoxy 43 (see FIG. 3). Inner tube 41 has a generallyplanar end surface 46 disposed proximal of tube orifice 28 forfacilitating the removal of the electrolytic solution from the skin ofthe patient. It can be seen from FIG. 4 that end surface 46 is disposedat the distal end or tube proximal portion 31 adjacent pliable distalend 32. Second passageway 42 is diametrically sized so as to permit areturn flow of electrolytic solution which can approximate the supplyflow of the electrolytic solution through first passageway 27 of tube24.

A return tube 47 extends through handle 23 to proximal extremity 41 a ofinner tube 41. Return tube 47 has a passageway 48, shown in FIG. 7,extending longitudinally therethrough which communicates with secondpassageway 42. The return tube 47 extends from handle 23 to aconventional pressure sealed container 49 which is coupled to aconventional suction source (not shown) by tube 51 so as to provide anegative pressure within second passageway 42 for removing theelectrolytic solution from the skin of the patient.

Finger operable means is carried by handle 23 for regulating oradjusting the flow rate of the electrolytic solution through tubepassageway 48 and thus the amount of the electrolytic solutionaccumulating on skin 17 at orifice 28. In this regard, handle 23includes a generally planar top wall 56 having an elongate slot 57therein which is generally rectangular in shape (see FIGS. 6 and 7). Acylindrical member in the form of wheel 58 is disposed within slot 57.Suction control wheel 58 is formed with first and second rollers 61which are aligned on the longitudinal centerline of wheel 58 androtatably engage the underside of top wall 56 on either side of slot 57.Return tube 47 extends below the top wall 56 and rests upon a generallyplanar surface 62 which faces the underside of top wall 56 and isinclined at a slight angle to the top wall. Support surface 62 is spacedfrom top wall 56 and suction control wheel 58 is diametrically sized sothat as the wheel 58 rolls within slot 57 toward tube 24, the wheel 58presses further downwardly into the flexible return tube 47. Thus, thecross-sectional area of passageway 48, and the rate of flow throughpassageway 48, is reduced in proportion to the travel of suction controlwheel 58 upwardly through slot 57. Disposition of wheel 58 at the bottomof slot 57 results in an unobstructed passageway 48 and thus full flowthrough return tube 47. Conversely, positioning of wheel 58 at the topof slot 57 near tube 24 results in closure of return tube passageway 48.A portion of the outer cylindrical surface of suction control wheel 58extends above top wall 56 to facilitate rolling of the wheel upwardlyand downwardly within slot 57 by a thumb of the operator. As illustratedin FIG. 6, gradations are provided alongside slot 57 on the outside oftop wall 56. Accordingly, the rate of flow through return tube 47 can bedetermined by the position of wheel 58 on handle 23.

An electrode 66 is carried by distal extremity 24 of tube 24 forproviding electrical energy to the electrolytic solution being suppliedto skin 17 through first passageway 27. Electrode 66 is made from anysuitable conductive metal such as stainless steel, platinum, gold orsilver and, as shown in FIGS. 2, 4 and 5, is ring-like or circular inconformation. More specifically, electrode 66 is oval in conformation.At least one opening in the form of hole 67 extends through the centerof ring electrode 66 for permitting the electrolytic solution to flowthrough the electrode 66. Electrode 66 is disposed within firstpassageway 27 proximal of orifice 28 by any suitable means such as anadhesive (not shown) and, as shown in FIGS. 2 and 4, is secured tocylindrical inner surface 29 at the end of tube proximal portion 31. Theelectrode 66 is aligned parallel with end surface 33 and is spaced fromthe end surface 33 and orifice 28 by a distance equal to the length ofdistal end 32.

Means for supplying radio frequency energy to electrode 66 includesradio frequency generator and controller 68. Lead means in the form ofelectrical wire 71 serves to connect generator 68 to electrode 66. Thewire 71 extends through handle 23 and first passageway 27 and has adistal end electrically coupled to electrode 66. The proximal end ofwire 71 is carried by a cable 72 which connects RF generator andcontroller 68 to handle 23. A conventional on/off switch 73 is coupledto the wire 71 in handle 23 and is included within the finger operablemeans of device 16 for controlling the supply of radio frequency energyto electrode 66. Alternatively, said finger operable means can be of atype to vary the power from generator 68 to electrode 66 and be withinthe scope of the present invention.

Temperature sensing means in the form of thermocouple 76 is carried bydistal extremity 24 b of tube 24 for monitoring the temperature of theelectrolytic solution at orifice 28 (see FIG. 6). Thermocouple 76 ismounted to inner surface 29 of tube proximal portion 31 in the vicinityof electrode 66 by any suitable means such as an adhesive (not shown)and extends proximally through tube 24 to handle 23. The thermocouplewire 76 extends through cable 72 to controller 68. Controller 68 andelectrode 66 also permit the impedance of skin 17 and the tissue withinthe body of the patient to be monitored.

In operation and use, radio frequency device 16 serves to introducemonopolar radio frequency energy through the skin of a patient totighten the outer surface of the skin. Radio frequency device 16 isparticularly suited for treating wrinkles 18 for cosmetic purposes bytightening the skin 17 forming the wrinkle and thus reducing thewrinkle.

The patient to be treated is prepared by placing an indifferentelectrode (not shown) on the backside of the patient and electricallycoupling the indifferent electrode to radio frequency generator andcontroller 68. Radio frequency device 16 is prepared by coupling supplytube 36 to the supply container 37 having the electrolytic solutiontherein. Variable IV clamp 38 is closed to preclude the solution fromflowing through tubes 36 and 24. Return tube 47 is connected to suctioncontainer 49 which, in turn, is connected to the suction source by meansof tube 51. Suction control wheel 58 is positioned at the top of slot 57so as to crimp and close off return tube 47.

The power requirements of radio frequency device 16 are a function ofseveral factors, including the amount of power applied to electrode 66,the size of electrode 66, the area of orifice 28, the temperature of theelectrolytic solution supplied through first passageway 27 and the rateof flow of the electrolytic solution through the first passageway. Inthis regard, radio frequency energy is delivered by electrode 66 atpower levels which can range from 10 to 50 watts with the surface areaof the electrode 66 ranging from 0.3 to 1.5 square inches. Theelectrolytic solution supplied through first passageway 27 has atemperature ranging from 10° to 37° C. and preferably approximately 20°C. The flow rate of the electrolytic solution through first passageway27 ranges from 50 to 400 drops per minute and more preferably rangesfrom 200 to 300 drops per minute.

The operator grasps radio frequency device 16 by handle 23 to positiondistal end 32 against skin 17 so that end surface 33 engages the skinand orifice 28 extends over wrinkle 18 as shown in FIG. 1. The flow ofthe electrolytic solution is commenced through first passageway 27 byadjustment of IV clamp 38 and suction control wheel 58 is rolleddownwardly through slot 57 to desirably adjust the return flow of theelectrolytic solution. The relative flow rates between first passageway27 and second passageway 42 can thus be adjusted to permit theelectrolytic solution to puddle in orifice 28 atop wrinkle 18 before theliquid is removed from skin 17 by means of inner tube 41. In thisregard, once the maximum desired flow through tubes 36 and 24 has beenprovided by adjustment of clamp 38, the operator can adjust the amountof electrolytic solution accumulating at tube distal extremity 24 b bymerely adjusting the outflow of the solution through tubes 41 and 47.The clear material of tube 24 permits the operator to visualize andmonitor the electrolytic solution accumulating inside distal extremity24 b to facilitate the adjustment of the flow rates in passageways 27and 42 The flexible and conformable material of distal end 32 inhibitselectrolytic solution from seeping out onto skin 17 around orifice 28.

Once the desired flow of electrolytic solution into first passageway 27and out of second passageway 42 has been obtained so as to cause theelectrolytic solution to accumulate in tube 24 to the level of electrode66, the operator of radio frequency device 16 pushes button 73 tocommence the supply of radio frequency energy to electrode 66. The radiofrequency energy from electrode 66 is carried by the electrolyticsolution to the outer surface of skin 17. Electrode 66 is in closeproximity to orifice 28 and skin 17 so as to minimize energy lossesbetween the electrode and the skin. The radio frequency energy from theelectrolytic solution travels through the skin into the body of thepatient to the indifferent electrode. The return of the radio frequencyenergy from the indifferent electrode to generator and controller 68completes the electrical circuit. The radio frequency energy causesoscillation of the ions in the intercellular solutions of the skin so asto create thermal energy.

The concentration of radio frequency energy is greatest at the skin 17underlying orifice 28 and is reduced exponentially as a function of thedistance from the radio frequency source, that is the distance beneathskin 17 from orifice 28. Specifically, the temperature effects fromradio frequency energy are determined by the following equation:

Temperature rise=(k)(I ²)(t)/(r ⁴)

where “k” is a constant for a given power impedance condition, “I”equals current, “t” equals time and “r” is the radius or distance fromthe radio frequency source, that is the electrolytic solution at theouter surface of skin 17. In FIG. 8, the temperature of the skin 17produced by radio frequency-induced molecular friction as a function ofthe distance beneath skin 17 is depicted by the dashed line 81. As canbe seen, the radio frequency-induced temperature is greatest in theouter layer or epidermis of skin 17 adjacent orifice 28.

The electrolytic solution additionally serves to cool skin 17 at orifice28 thus counteracting the effects of molecular friction caused by theradio frequency energy passing through the skin surface. The actualtemperature of skin 17 as a function of the distance below the surfaceof the skin is shown by the solid line 82 in FIG. 8. As can be seen inFIG. 8, the effects of cooling by the electrolytic solution diminish atlevels below the skin surface. Thus, the temperature in these lower skinlevels is high relative to the temperature of the outer layers of theskin. In this manner, the thermal heating of the dermis layer of theskin 17 is achieved with reduced heating of the epidermis layer of theskin 17.

The transmission of radio frequency energy through the skin 17 resultsin a secondary temperature rise at skin depths where the temperatureeffects from molecular friction are rapidly decreasing. This temperaturerise is caused by conductive heating generated from radiofrequency-induced molecular friction. It can be seen from FIG. 8, forexample, that the actual temperature 82 of the skin 17 crosses over theradio frequency temperature 81 at approximately 1.8 millimeters belowthe surface of the skin so that the actual skin temperature 82 isapproximately 5° to 10° higher than the radio frequency-inducedtemperature of skin 17 at distances greater than approximately 1.8millimeters below the surface of the skin.

The optimal heating profile or gradient of skin 17 is set forth in FIG.8. As shown therein, a more uniform temperature distribution is obtainedacross the wall of the skin than would be achieved by merely heating thesurface of the skin. Specifically, the skin temperature two millimetersbelow the surface ranges from 62° to 70° C. and preferably approximately65° C. This dermis temperature is maintained for a period ranging fromone to four seconds. The skin temperature decreases exponentially in thedeeper layers of the skin. The desired temperature in the epidermislayer of skin 17 is 60° C. or less, preferably ranging from 37° to 60°C. and more preferably approximately 55° C. The temperature of skin 17is monitored by means of thermocouple 76 at controller 68, which cancalculate the skin temperature from the temperature of the electrolyticsolution at thermocouple 76. The impedance of skin 17 is also monitoredat the controller 68. The procedure at a particular site on skin 17 canbe terminated, either manually or automatically, if the skin temperatureor impedance reach certain levels.

The flow of radio frequency energy through skin 17 denatures thecollagen molecules within the skin and thus serves to tighten the outerlayer or epidermis of the skin being treated. In this regard, the radiofrequency induced thermal energy breaks apart the heat sensitive bondsbetween the fibrils of the trifibrillar helix in the collagen molecules.When these bonds are broken, each of the fibrils shrinks to a shortenedor contracted state. Once the thermal heating is reduced, the fibrilscross-link in a random coil as opposed to the organized fibril networkwhich existed prior to heating. This contraction of the collagen stromaserves to similarly contract the outer layer of skin 17.

Radio frequency device 16 serves to enhance collagen shrinkage in skin17 by increasing the flow of radio frequency energy to the dermislayer-of the skin. Since greater amounts of collagen exist in the dermislayer than in the epidermis layer of skin, it is desirable that theradio frequency induced thermal energy be concentrated in the dermislayer rather than in the epidermis layer. The radio frequency energyfrom device 16 creates a slow heating of skin 17 so as to permittemperatures in the dermis layer to rise without necrosis and charringto the epidermis. Such charring causes undesirable impedance rises inthe epidermis layer of the skin 17 which decreases the electricaltransmissivity of the epidermis layer and thus the flow of electricalenergy to the underlying dermis layer. The thermal heating of theepidermis is decreased, as illustrated in FIG. 8, by the continuouscooling of the epidermis from the flow of electrolytic solutiontraveling through tube 24.

The method of the present invention is less painful to the patient thanexisting procedures. The cooling of the outer layer of skin 17 minimizespainful burns which would otherwise result in these layers. The spacingof electrode 66 from skin 17 also reduces the likelihood of skin burnsby inhibiting intimate contact between the thermally hot electrode andthe skin. The deep penetration of the radio frequency energy reducespain to the patient by deadening nearby nerve endings in the skin. Inaddition, the level of sloughing of the outer layers of skin 17 isdecreased.

The operator of radio frequency device 16 moves distal end 32 along thewrinkle 18 or the other portion of the skin 17 being treated. Thismovement can be in sequential steps or in a continuous motion. The flowof electrolytic solution and radio frequency energy through tube 24 iscontinuous during such movement and the conformable material of tubedistal end 32 acts as a squeegee to remove the electrolytic solutionfrom skin over which it passes. In this manner, the desired portion ofskin 17 is treated.

Upon completion of the procedure, button 73 is depressed to cease theflow of electrical energy from radio frequency generator and controller68. IV clamp 38 is closed off to cease the flow of the electrolyticsolution to radio frequency device 16 and supply tube 36 is disconnectedfrom supply container 37. Suction control wheel 58 is rolled upwardly inslot 57 once any remaining electrolytic solution on the skin of thepatient has been removed through return tube 47.

It should be appreciated that orifice 28 can be rectangular in shape orhave other shapes. The radio frequency device of the present inventioncan also have interchangeable tubes 24 and/or distal ends 32 foraccommodating different contours in the surface of skin 17. Leakage ofthe electrolytic solution can thus be further minimized. Electrolyticsolutions with higher viscosity will also be less susceptible to leakingfrom distal end 32 of the device 16. More consistent applications areprovided with larger orifices 28. However, such larger orifices requiremore radio frequency power.

From the foregoing it can be seen that a new and improved radiofrequency device and method for resurfacing skin has been provided whichminimizes burning of the superficial layers of the skin. Collagenmolecules in the skin are denatured to tighten the epidermis layer ofthe skin and thus resurface the skin. Radio frequency energy is carriedby an electrically conductive liquid to the surface of the skin. A flowof the electrically conductive liquid engages the skin to actively coolthe skin.

What is claimed is:
 1. A method for treating a patient having skin withcollagen and an outer surface by use of a device having a rubber endportion provided with an opening and a reservoir of cooled electrolyticsolution coupled to the device comprising the steps of placing theopening over the outer surface of the skin, supplying a cooledelectrolytic solution from the reservoir to the opening and onto theouter surface of the skin and introducing radio frequency energy intothe electrolytic solution to pass radio frequency energy through theskin so as to denature the collagen in the skin and tighten the outersurface of the skin.
 2. The method of claim 1 further comprising thestep of removing the cooled electrolytic solution from the outer surfaceof the skin and supplying additional cooled electrolytic solution fromthe reservoir to the opening and onto the outer surface of the skin soas to continuously cool the outer surface of the skin during theintroducing step.
 3. The method of claim 1 wherein the supplying stepincludes the step of providing a continuous supply of cooledelectrolytic solution to the opening and onto the outer surface of thesldn during the introducing step.